Slot machines have been a form of entertainment to the public for many decades. They began as mechanical, three-reel devices that, through mechanical means, were made to rotate and then to separately come to a stop; each at a distinct location along the reel. The result would be a series of symbols or blanks—one per reel—that would be displayed horizontally along a payline, each symbol or blank being one in a set of symbols or blanks included on the reel strip. Each displayed symbol or blank corresponded with a distinct stopping point associated with the respective reel. The given combination of displayed symbols or blanks along the payline, which corresponded to the given sequence of stopping points, provided a specific, pre-determined result. When a wager was made to initiate this mechanical action, the pre-determined result would be a winning, losing or draw situation where the player would either be compensated over and above the value of the wager made, lose his wager or receive back his wager. For instance, the combination of an orange symbol on the first reel stop, ‘7’ symbol on the second and a blank on the third might correspond to a losing result and therefore nothing would be distributed to the player resulting in a complete loss of the player's wager. A cherry symbol in the first reel followed by any two other symbols or blanks might result in a draw whereby the player's wager would be returned but with no distribution of additional monies. A series of ‘7’ symbols on each reel might be a winning result awarding the player with a return greater than the amount of the player's wager.
While this simple form slot machine provided entertainment, it has been the continuous goal of slot machine developers to develop slot machines, including the games that reside therein, with ever-increasing entertainment value. The higher the entertainment value of the machine, the greater its use and therefore, generally, the greater revenue yield for the house (since by mathematical design the house always retains a certain percentage of the monies wagered over time). Thus, this basic form of slot machine has evolved with great strides over the years to satisfy this goal. Some of these include:
Video Representations of Reels: The slot machines of the past have taken a new direction and are now also manufactured as electronic gaming machines. These gaming machines now display reel-like images on a video monitor and are activated through electronic input and controlled through processors that execute code-based computer instructions. The reel images once activated are displayed as spinning reels with each individually coming to a stop based on a time-dependent algorithm.
Computer-generated Symbol Images and Animations: The symbols of the reel strips are generated as computer images which generally appear within a symbol matrix when the reels are shown to stop on the gaming machine monitor. On some displays, the symbols are visible as the reel images spin. Additionally, since the gaming machine is now essentially a computer having a high-resolution monitor, animated images and visual effects can be created and displayed at the symbol locations to further enhance entertainment value.
Touch Screens: A touch screen interface is deployed on many of today's gaming machine monitors. This allows the player to interact more with the game. Among other things, the player can choose paylines, denomination, control the volume, choose when to initiate action, even determine with a degree of precision when an individual reel will stop. The interface detects the players touch on the gaming machine monitor through a change in resistance or capacitance at the location in which the monitor is touched and transfers this as spatial input data to the gaming machine processor, which processes the function intended to be affected at that location.
Theme Games: The typical “fruit” games that displayed symbols generally of various fruits, the number ‘7’ and blank spaces matured into various themed games that used symbols associated with the theme and theme-related graphics in the glass displays of the machines to attract players. To amplify on this, certain well-known brands were licensed by the gaming machine developers; perhaps the best known being the WHEEL OF FORTUNE® brand licensed by gaming machine manufacturer and developer IGT.
Multiple Selectable Paylines: Gaming machines began by displaying results along only one payline. Now multiple paylines exist. The player need not be limited to the result indicated by the symbol combination displayed horizontally from the first reel to the last reel along one row. Now the player may select varying payline paths and therefore varying numbers of paylines. The player is generally only limited by the mathematical combinations of symbol paths aligned from the first reel to the last reel. In a symbol matrix having three by five (3×5) symbol positions, this equates to 243 different pay lines.
Virtual Stops: The symbol combinations resulting from the early slot machines were wholly dependent on the mechanics of the machine. Although it was by random chance, the reel was stopped exclusively by the mechanics of the machine. Therefore, any symbol or blank had the same mathematical probability of being displayed as the selected symbol along the payline as any other symbol or blank on that reel. Therefore, if there were 50 symbols per reel and only one of those symbols was, for instance, a ‘7’ symbol, there would be a 1 out of 50 chance of the ‘7’ symbol being displayed and, for a three reel slot machine each having the same 1 out of 50 chance, a 1 out of 125,000 chance of a ‘7’ symbol being displayed on all three reels. This limited the amount of win that could be awarded to the player. If one nickel were wagered, no more than $6,250 dollars (125,000 nickels) could be awarded else the advantage to the house would be lost. Although significant, this amount—the highest that could be given for this described machine of three reels with 50 potential positions per reel—only provided so much entertainment value given that the award was not a life altering event. With the advent of random number generators, a software program that can randomly select a number from any set of numbers with each number having the same stochastic probability of being selected as the next, games could be designed whereby the selected number would provide the symbol combination result. Each number in the set of numbers would be assigned or “mapped” to a specific symbol combination. For each number selected, the game programming would map the given result to the reels and the assigned symbol combination would be displayed. Thus, in the same example as above, instead of having only a 1 in 125,000 chance of obtaining the symbol combination of three ‘7’s along the payline, there could be any number of probabilities. If the set of numbers was one million and only one of those numbers was mapped to the triple ‘7’ symbol combination, then there would be a one in a million chance of the random number generator selecting that number and displaying the triple ‘7’ combination on the gaming machine monitor along the selected payline. An award in the neighborhood of $5,000,000 could then be provided—a life altering award and a game that a player would generally be more inclined to play.
Variable Denomination: Legacy slot machines accepted coins of a certain, specific denomination. Therefore, a player had little choice but to play the slot machine game by inserting a nickel, dime or quarter, as required by the particular machine. Only if the same game existed on more than one machine and those machines had differing denominations would a player have some choice in determining the wager he wished to make on a certain game. Gaming machines of today accept currency, coin and credit through varying input devices; be it a coin collector for accepting coinage, bill validator for accepting paper currency, a ticket validator for accepting monetized, secure tickets, or a smart card device that may accept debit cards, credit cards or the like. When received, the amount is recorded on the machine (and may be debited or credited against the smart card). A denomination can then be selected and the gaming machine logic records credits to the machine, which is simply the result of the monetary amount input to the machine divided by the denomination selected. With this capability the player can not only select the denomination for each game played, but for a given wager amount the player can now select a lower denomination and spread the wager out over numerous paylines. For instance, if the player wishes to wager one dollar, some of the options the player would have for making that wager would be: (i) select one dollar as the denomination and bet it on one payline, (ii) choose quarter denomination and wager on four selected paylines, (iii) choose quarter denomination and wager fifty cents for each of two selected paylines, (iv) choose penny denomination and wager ten cents for each of ten selected paylines. This type of flexibility and ability to play more pay lines generates greater excitement for the player.
Bonus Games: A variety of different bonus games, both mechanical and computer-animated, are now included with many gaming machine games. They can be triggered either randomly or through a specific triggering event from the initial or base game. Some bonus games are simply additional, free plays of the base game. Sometimes the base game may be modified in some fashion to create more interest. Other times the bonus game is entirely separate from the base game though it may be displayed either in the same monitor as the base game, a secondary monitor, or it may be a separate device associated with the gaming machine (a well know example of this would be the physical, spinning wheel used with the WHEEL OF FORTUNE® casino game developed by IGT). Sometimes the bonus game will require player interaction and sometimes it will not. For instance, the Wheel of Fortune game, whether through a physical spinning reel or a simulated reel displayed in a computer monitor, only requires that the player initiate a spin. The wheel then spins. When it stops, the award provided to the player is displayed at a given marker. Player interaction may be required in bonus games where the player selects one of a number of options and is given an award or some other result based on the selection. There are a multitude of different bonus-type games and methods. Much of today's game design is geared towards coming up with new and innovative type bonus events to further amuse and entertain the player.
Progressive Jackpots: Progressive jackpots are variable jackpot amounts that grow over time and are funded through contributions made by each player that is given a chance at winning the jackpot. The contributions are made from a portion of the wager made for play of the base game. Therefore, the jackpot continuously grows until it is won and then reset to some pre-determined lower value. These jackpots can be dedicated to a singular gaming machine but are more often associated with a bank of gaming machines that link to a computer server that controls all aspects of the jackpot through a network. These jackpots can be associated with a particular win on the base game, randomly awarded, or associated with a particular win in a bonus game. They are very attractive to players due to the fact that they can grow very large over time and because, when associated with a bank of machines, they provide a sense of enjoyed community among the players. Sometimes there games include progressive jackpot levels. These games split up the progressive jackpot awards contributing a portion of the wager to one distinct jackpot, and one or more differing portions to one or more other distinct jackpots. The jackpot awarded would vary depending on the outcome of the game, with the largest jackpot being awarded for the outcome having the least probability of occurrence.
Networks: Creating a network of gaming machines is now standard practice in most casinos and other gaming locations. The prime reasons for networking is to automate and centralize accounting for all machines on the gaming floor, to track individual players' gaming results and activities, to gain knowledge of game productivity, and to deliver games and other media from a central server to the individual gaming machines. But networks are also established among a bank of gaming machines in order to create shared bonus games and awards. Progressive jackpots are variable jackpot amounts that grow over time and are funded through contributions made by each player that receives a chance at winning the jackpot. The contributions are taken from a portion of the wager made towards play of the base game. Therefore, the jackpot continuously grows until it is won and then reset to some lower value. These jackpots can be dedicated to a singular gaming machine but are more often associated with a bank of gaming machines.
Wagering and Bonus Games: As discussed above, bonus games have become commonly used with gaming machines. They are an attractive, added part of the gaming experience. Funding of the bonus game comes from the wager made toward play of the base game. A portion of the payback percentage is attributed to the base game and a portion is attributed to the bonus game. Game developers have designed the bonus games so that the awards provided are increased in proportion to the wager made per payline or the total wager. This ensures that a constant payback percentage or expected return to the player is maintained with increasing or decreasing wager. On some bonus games, a jackpot award—typically the largest award of multiple awards available in the bonus game—may only be made available to the player if the player makes the maximum credit wager. This may change the payback percentage when the maximum credit wager is made, but it has been permitted by gaming regulators and provides incentive to the player to make the maximum credit wager. Other variations maybe provided with wager. In U.S. Pat. No. 6,186,894 by Mayeroff, the number of spins given to a player in a bonus game is dependent on the wager. That number can be determined by the number of paylines selected or the number of credits played per payline. The bonus game is triggered by a specific result in the base game. Thus, the player can be rewarded and incentivized for making an increased wager by being provided additional chances in a bonus round whence the bonus round is triggered. U.S. Pat. No. 7,056,215 by Olive describes a random bonus triggering method. In that patent, although the bonus event is provided at random, the chances of obtaining the bonus are increased in proportion to the amount wagered. In U.S. Pat. No. 7,8268,643 by Baerlocher, the probability of triggering a bonus is increased in proportion to the amount of paylines selected, similar to Mayeroff. However, this patent also describes varying odds at different levels of a bonus whereby the odds at each level are affected by the wager made per payline and not based on the number of paylines selected.